But because plays — and especially musicals — bring together so many disparate artistic elements, from story to song to (often) choreography and other interpretive techniques, they seem especially susceptible to competing claims on their creation.

“Theater is a very collaborative art form,” as Rosenberg says. “And so when you’re developing something new and you’re in a rehearsal room — who owns that stuff?”

In times past, when copyrights were less rigorously enforced and attitudes about artistic license were perhaps more relaxed, “borrowing” of all sorts was tolerated. It’s well known that Shakespeare, for example, appropriated plots and scenarios from earlier works for many of his plays.

Fast-forward 400 years to our time, when not only playwrights but even directors and other theater artists scramble to copyright their work. So, with some irony, comes a work like “Shakespeare’s R&J,” a 1998 re-imagining of “Romeo and Juliet” by the director and adapter Joe Colarco.

The words in that play are almost entirely Shakespeare’s (whose works have been in the public domain for centuries), but Colarco copyrighted the piece in his own name because it uses a specific framing device and unique aspects of staging.

When it comes to plays derived from movies, rights-holders behind the films also have become much more savvy about the economic prospects of a stage adaptation.

“Twenty years ago, an independent (theater) producer could go to a movie studio and get the rights to a film fairly easily and reasonably,” says Ralph Sevush, an executive director of the Dramatists Guild, which advocates for playwrights.

“That doesn’t happen anymore because the studios are aware of the value of those properties. It just never was on their radar before.”

Such vigilance, along with the subjective nature of judging how a story has been adapted or derived, can make putting together a production based on a movie or other established work very complicated. Rosenberg uses the fictional example of a musical that takes the movie “Star Wars” as inspiration.

“So then you get into, is (so and so playwright’s) ‘Star Wars’ based on George Lucas’ ‘Star Wars’? Or is it based on the story of Moses, which is in the public domain?”

It so happens that “A Gentleman’s Guide to Love and Murder” also revolves around a character who discovers he has royal blood — emphasis on the “blood.”

As Playhouse artistic director Christopher Ashley described the piece when announcing the new season in January, the musical is about a man who learns he’s a half-dozen or so spots back in line for a royal title, “and decides he’s going to knock off anybody in his way.”

Tony-winner Jefferson Mays (“I Am My Own Wife”) was to play all the victims of the murderously ambitious character. Darko Tresnjak, who served as resident artistic director of the Old Globe Theatre until last year, was to direct.